It is clear, then, that the earth must be at the centre and immovable, not only for the reasons already given, but also because heavy bodies forcibly thrown quite straight upward return to the point from which they started, even if they are thrown to an infinite distance. From these considerations then it is clear that the earth does not move and does not lie elsewhere than at the centre.

Happiness is a sort of action.

The true end of tragedy is to purify the passions.

All men seek one goal: success or happiness.

The knowledge of the soul admittedly contributes greatly to the advance of truth in general, and, above all, to our understanding of Nature, for the soul is in some sense the principle of animal life.

We must speak first about the division of land and about those who cultivate it: who should they be and what kind of person? We do not agree with those who have said that property should be communally owned, but we do believe that there should be a friendly arrangement for its common use, and that none of the citizens should be without means of support.

That rule is the better which is exercised over better subjects.